An Application of Direct-Sequence Spread-Spectrum Ultrasonic to Global Inspection of Bridge Components

Abstract

Direct-Sequence Spread-Spectrum Ultrasonic Evaluation (DSSSUE) offers solutions to unsolved inspection problems. A “better mouse-trap”, i.e., an improvement in technology that offers an alternative solution to problems that already have adequate solutions, generally does not make it in the market place for economic reasons. We cannot over-emphasize this aspect of the technology as there must be a clear perception of “new technology” and that the new technology is automatically economical, because it offer solutions were none existed before. DSSSUE incorporates a correlation receiver. The correlation peak to correlation noise floor effectively determines the “dynamic range” of the system and, therefore, its sensitivity. The sensitivity of DSSSUE is essentially limited by the cost of the technological implementation (memory and quantization levels) and processing time (length of correlation sequence). This results in a new technology that can be made extremely sensitive to changes in a test object, is operable over a broad range of frequencies, and is adaptable to a large number of inspection scenarios, including bridge components.